canary yellow diamond with cavity at bezel facet

Does this “hole” on the diamond’s surface scare you when viewing it under magnification?

Is this a cause for concern when you are making choices in diamond selectings? Well, it depends. First of all, what is a cavity and how is it formed? Basically, a cavity inclusion is just another name for a hole in the diamond. 

In most cases, a cavity is created during the polishing process when a feather near the surface is breached or when a crystal inclusion gets dislodged from the diamond’s body. This creates an empty void and leaves an opening on the diamond’s surface.

An Illustrated Example of Diamond Cavity Formations (Indicated by Red Arrows)

polishing diamonds with inclusions near and breaking to surface

Inclusions like feathers, clouds or crystals can break to the surface during cutting…

Now, you might be wondering why didn’t the cutter polish off the cavity if they could do so. The answer boils down to economics. Most of the time, it would require a severe weight loss of the rough stone in order to completely remove a cavity inclusion. As a result, most cutters opt to retain weight at the expense of lower clarity grades since the value of a heavier diamond is usually higher.

Personally, I don’t like having cavities as inclusions in my diamond. I tend to avoid cavities in SI1-SI2 diamonds especially if they are the clarity grade makers. The reason behind this is that bigger cavities tend to turn dark with normal wear due to trapped dirt and oil. To illustrate this, here are a couple of diamond examples I would avoid…

cavity in si2 cushion cut diamond

Without regular cleaning, dirt can accumulate and create a dark appearance.

Location Matters When It Comes to Inclusions

cavity in a diamond's pavilion facet

If the cavity gets clogged, how would you clean the stone effectively?

In this example, the cavity is found on the bottom (pavilion) side of the stone. You need to tread carefully here and make sure that the cavity isn’t large enough to be an issue. The reason behind this is that once the stone is set, it would be very difficult for effective cleaning if dirt gets into the crevice.

The location of the cavity and diamond’s clarity grade also plays a huge role too. For example, if they are located in an inconspicuous area, they are usually more acceptable and won’t be easily noticed by a casual viewer.

heart shaped diamond with cavity at wing area

Example of a great looking SI2 diamond with no significant clarity issues.

When Is It a Bad Thing? – An Example of One Such Diamond…

marquise diamond with cavity at girdle

Huge cavity at girdle creates an awful looking dark patch and also causes durability issues.

Every once in a while, VS clarity diamonds with cavities do show up. Generally speaking, diamonds with clarity grades of VS2 or better would not have durability issues and are relatively “safe” choices. Most of the time, inclusions found in VS stones are insignificant and don’t negatively affect the diamond’s appearance.

Of course, it doesn’t hurt to be doubly sure and have the diamond checked by a professional. In the oval cut example above, we see a rare case where a VS2 clarity grade consists of inclusions that are detrimental to the diamond’s beauty and durability.

Conclusion

Like any other types of inclusions, alot depends on the nature of the inclusions being benign or malign. If you are considering a diamond with cavity inclusions, I recommend examining the inclusions at different viewing angles with a microscope. You should always consider the cavity’s depth and exposed surface size before coming to a decision to reject or purchase the stone.

James Allen lets you inspect diamonds up close with 360° videos. This allows you to see the actual diamond without having to use a loupe and helps you make better decisions.

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2 Comments

  1. Avatar
    Cedric-
    March 11, 2019 at 9:31 pm

    Thank you so much for the website, it is very insightful.

    I visited a shop and was presented this diamond https://www.gia.edu/report-check?reportno=2287233768

    My wife really liked it because of the size, dimensions and the spread of the diamond.

    It was proposed to me for $14500. I don’t think the price is worth it but what do you think about the quality of it.

  2. Avatar
    Paul Gian-
    March 12, 2019 at 6:43 am

    It’s hard to say and I cannot pass any judgment on a cushion cut diamond without looking at details and videos. Cut quality of a cushion would best be assessed via an ASET image. This page has examples of what to look for: https://beyond4cs.com/grading/aset-reference-charts/

    If you haven’t yet, make sure you read this tutorial on cushion shapes too: https://beyond4cs.com/shapes/cushion/

    If cut quality and performance checks out, then I would go ahead and look at clarity issues. I would be wary of the feather and cavities for an SI2 diamond and this is something you MUST check for eyecleanliness before buying.

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